1. Field of the Invention
The present invention relates to shoring systems for supporting the sides of an excavation to prevent cave-ins.
2. Description of the Related Art
Shoring systems are used to “shore” (support) the earthen walls of an excavation to help prevent cave-in around workers. A shoring system typically includes a pair of opposing side walls driven forcibly outward by hydraulic actuators against earthen walls of the excavation. Shoring therefore protects workers doing work in the excavation, such as below ground repairs, maintenance, or installations such as laying a pipeline. Excavations may be deep and the soil in and surrounding the excavation may be unstable, which poses a risk to workers. Therefore, it is important to use a reliable shoring system capable of withstanding the large pressures that can be exerted by earthen walls. It is also important to use a shoring system that can be easily controlled, such as to drive the side walls outward and maintain pressure against the earthen walls of the excavation. It is critical for a shoring system to be easily controllable in case of an emergency, as well as for efficiently inserting and subsequently removing the shoring system from the excavation.
FIG. 1 shows a conventional shoring system 1, having a pair of spaced-apart side walls 2 each equipped with an upper cap 8 and lower skid 9. A pair of supporting rails 3, also known in the art as wales, are mounted in parallel along the inner faces of each side wall 2. The side walls 2 are connected by telescoping cross members, 4a, 4b The ends of the cross members 4a, 4b are mounted in channels defined by opposing wales 3. A hydraulic jack or cylinder 10 is mounted proximate each cross member, and the ends of each hydraulic jack are also mounted, via respective pads, in the channels of the opposing wales 3. The hydraulic jacks operate to expand or contract the space between the side walls 2, and provide compressive preloading of the walls of an excavation to prevent or at least reduce the likelihood of a cave-in. A coiled steel closure spring 7 helps draw together the side walls 2, during removal of the assembly 1 from an excavation. The hydraulic jacks 10 distribute hydraulic fluid pressure to the hydraulic jacks 10 by way of a stationary manifold assembly 21. The manifold assembly 21 may include a bored, block manifold body (not shown) secured to a side wall 2, some valves and other fluid control devices, and a shield 28 bolted to the block manifold body. Hydraulic lines 41 are routed from the manifold assembly 21 to the jacks 10 by way of a channel in one of the wales 3.
The configuration of the conventional manifold 21 limits a user's ability to access the block manifold body, such as to connect and disconnect hoses or to control the supply of hydraulic fluid to the hydraulic jacks. The user's ability to quickly and easily control the movement of the side walls 2 is thereby limited. In the even of an emergency, a user may be unable to access the manifold to control the side walls 2. Even under normal operating conditions, the lack of access a user has to the manifold reduces the efficiency by which the conventional shoring system 1 may be operated. Therefore, an improved shoring system is needed for faster, safer, more reliable, and more convenient operation by a user.